gold_land_server/test/gold-precision.test.ts

/**
 * Gold trade precision + no rounding-arbitrage — temp SQLite only.
 * Run: npm run test:gold-precision
 */
import assert from 'node:assert/strict'
import { mkdtempSync, rmSync } from 'node:fs'
import { tmpdir } from 'node:os'
import { join } from 'node:path'
import { ValidationPipe, BadRequestException } from '@nestjs/common'
import { Test } from '@nestjs/testing'
import { FastifyAdapter, NestFastifyApplication } from '@nestjs/platform-fastify'
import { ApiExceptionFilter } from '../src/common/filters/api-exception.filter'
import {
  applyGoldPurchase,
  applyGoldSale,
  gramsToMicroGrams,
  normalizeGoldGrams,
  tomansForGoldGramsRound,
  tomansForGoldPurchase,
  tomansForGoldSale,
  GOLD_PRICE_TOMAN_PER_GRAM,
  MAX_GOLD_TRADE_GRAMS,
} from '../src/wallet/gold-trade.helpers'
import { createDefaultUserState } from '../src/shared/catalog/default-user-state'
import { GOLD_PRICE } from '../src/shared/catalog/market.constants'
import { DatabaseService } from '../src/database/database.service'

const testDir = mkdtempSync(join(tmpdir(), 'gold-land-gold-precision-'))
process.env.DB_PATH = join(testDir, 'test.db')
process.env.NODE_ENV = 'test'
process.env.PORT = '3996'
process.env.JWT_SECRET = 'gold-land-dev-secret-change-in-production'

function parseJson<T>(payload: string): T {
  return JSON.parse(payload) as T
}

function authHeader(token: string) {
  return { authorization: `Bearer ${token}` }
}

async function createApp(): Promise<NestFastifyApplication> {
  const { AppModule } = await import('../src/app.module')
  const moduleRef = await Test.createTestingModule({ imports: [AppModule] }).compile()
  const app = moduleRef.createNestApplication<NestFastifyApplication>(new FastifyAdapter())
  app.useGlobalPipes(
    new ValidationPipe({ transform: true, whitelist: true, forbidNonWhitelisted: true }),
  )
  app.useGlobalFilters(new ApiExceptionFilter())
  await app.init()
  await app.getHttpAdapter().getInstance().ready()
  return app
}

async function registerUser(app: NestFastifyApplication, username: string): Promise<string> {
  const res = await app.inject({
    method: 'POST',
    url: '/api/auth/register',
    payload: { username, password: '123456', name: username },
  })
  assert.ok(res.statusCode === 200 || res.statusCode === 201)
  return parseJson<{ token: string }>(res.payload).token
}

function assertNoCashArbitrage(initialCash: number, finalCash: number) {
  assert.ok(
    finalCash <= initialCash,
    `cash must not increase from rounding (initial=${initialCash}, final=${finalCash})`,
  )
}

function unitTests() {
  assert.equal(GOLD_PRICE_TOMAN_PER_GRAM, GOLD_PRICE)

  // Pre-fix symmetric round produced +1 toman on this split (5 buy, 6 sell).
  assert.equal(tomansForGoldGramsRound(0.000_003), 5)
  assert.equal(tomansForGoldGramsRound(0.000_001), 2)
  assert.equal(tomansForGoldPurchase(0.000_003), 6)
  assert.equal(tomansForGoldSale(0.000_001), 1)
  assert.equal(tomansForGoldPurchase(0.000_001), 2)
  assert.equal(tomansForGoldPurchase(1), GOLD_PRICE)
  assert.equal(tomansForGoldSale(1), GOLD_PRICE)
  assert.equal(tomansForGoldPurchase(0.05), Math.ceil(0.05 * GOLD_PRICE))
  assert.equal(tomansForGoldSale(0.05), Math.floor(0.05 * GOLD_PRICE))

  assert.throws(() => applyGoldPurchase({ cash: 1e12, goldGrams: 0 }, Number.POSITIVE_INFINITY), BadRequestException)
  assert.throws(() => applyGoldPurchase({ cash: 1e12, goldGrams: 0 }, 0), BadRequestException)
  assert.throws(() => applyGoldPurchase({ cash: 1e12, goldGrams: 0 }, 0.000_000_4), BadRequestException)

  const maxMicro = gramsToMicroGrams(MAX_GOLD_TRADE_GRAMS)
  assert.ok(maxMicro * GOLD_PRICE > Number.MAX_SAFE_INTEGER)
  assert.equal(tomansForGoldPurchase(MAX_GOLD_TRADE_GRAMS), MAX_GOLD_TRADE_GRAMS * GOLD_PRICE)

  const state = { cash: 10_000_000, goldGrams: 42.5 }
  const cost = applyGoldPurchase(state, 0.05)
  assert.equal(cost, Math.ceil(0.05 * GOLD_PRICE))
  assert.equal(state.goldGrams, normalizeGoldGrams(42.5 + 0.05))

  applyGoldSale(state, 0.001)
  assert.equal(state.goldGrams, normalizeGoldGrams(42.5 + 0.05 - 0.001))

  // 3 µg buy then three 1 µg sells — no cash gain.
  const arb = createDefaultUserState('arb')
  arb.cash = 1000
  arb.goldGrams = 0
  applyGoldPurchase(arb, 0.000_003)
  applyGoldSale(arb, 0.000_001)
  applyGoldSale(arb, 0.000_001)
  applyGoldSale(arb, 0.000_001)
  assert.equal(arb.goldGrams, 0)
  assertNoCashArbitrage(1000, arb.cash)

  // Aggregated sell vs split sells — same gold out, cash never above start.
  const agg = createDefaultUserState('agg')
  agg.cash = 500_000
  agg.goldGrams = 0
  const aggStart = agg.cash
  applyGoldPurchase(agg, 0.000_003)
  applyGoldSale(agg, 0.000_003)
  assert.equal(agg.goldGrams, 0)
  assertNoCashArbitrage(aggStart, agg.cash)

  // Many micro cycles at fixed rate.
  const repeat = createDefaultUserState('u')
  const startCash = GOLD_PRICE * 100
  repeat.cash = startCash
  repeat.goldGrams = 0
  for (let i = 0; i < 50; i++) {
    applyGoldPurchase(repeat, 0.000_001)
    applyGoldSale(repeat, 0.000_001)
  }
  assert.equal(repeat.goldGrams, 0)
  assertNoCashArbitrage(startCash, repeat.cash)

  // Buy small chunks, sell in one lump.
  const lump = createDefaultUserState('lump')
  lump.cash = 1_000_000
  lump.goldGrams = 0
  const lumpStart = lump.cash
  for (let i = 0; i < 10; i++) {
    applyGoldPurchase(lump, 0.000_001)
  }
  applyGoldSale(lump, 0.000_01)
  assert.equal(lump.goldGrams, 0)
  assertNoCashArbitrage(lumpStart, lump.cash)
}

async function seedWallet(
  app: NestFastifyApplication,
  token: string,
  cash: number,
  goldGrams: number,
): Promise<string> {
  const me = await app.inject({ method: 'GET', url: '/api/me', headers: authHeader(token) })
  const userId = parseJson<{ user: { id: string } }>(me.payload).user.id
  const db = app.get(DatabaseService)
  const row = db.getDb().prepare('SELECT state_json FROM users WHERE id = ?').get(userId) as {
    state_json: string
  }
  const state = JSON.parse(row.state_json) as ReturnType<typeof createDefaultUserState>
  state.cash = cash
  state.goldGrams = goldGrams
  db.getDb()
    .prepare('UPDATE users SET state_json = ?, updated_at = ? WHERE id = ?')
    .run(JSON.stringify(state), new Date().toISOString(), userId)
  return userId
}

async function apiRegressionScenario(app: NestFastifyApplication) {
  const token = await registerUser(app, `gold-round-${Date.now()}`)
  const initialCash = 1000
  await seedWallet(app, token, initialCash, 0)

  const buy = await app.inject({
    method: 'POST',
    url: '/api/wallet/gold/buy',
    headers: { ...authHeader(token), 'content-type': 'application/json' },
    payload: JSON.stringify({ grams: 0.000_003 }),
  })
  assert.equal(buy.statusCode, 200)
  const afterBuy = parseJson<{ wallet: { cash: number; goldGrams: number } }>(buy.payload)
  assert.equal(afterBuy.wallet.goldGrams, 0.000_003)
  assert.equal(afterBuy.wallet.cash, initialCash - tomansForGoldPurchase(0.000_003))

  let cash = afterBuy.wallet.cash
  let gold = afterBuy.wallet.goldGrams
  for (let i = 0; i < 3; i++) {
    const sell = await app.inject({
      method: 'POST',
      url: '/api/wallet/gold/sell',
      headers: { ...authHeader(token), 'content-type': 'application/json' },
      payload: JSON.stringify({ grams: 0.000_001 }),
    })
    assert.equal(sell.statusCode, 200)
    const body = parseJson<{ wallet: { cash: number; goldGrams: number } }>(sell.payload)
    cash = body.wallet.cash
    gold = body.wallet.goldGrams
  }
  assert.equal(gold, 0)
  assertNoCashArbitrage(initialCash, cash)
  assert.notEqual(cash, initialCash + 1, 'old symmetric round would have created +1 toman')
}

async function apiTests(app: NestFastifyApplication) {
  await apiRegressionScenario(app)

  const token = await registerUser(app, `gold-precision-${Date.now()}`)
  await seedWallet(app, token, 500_000, 0)

  const subToman = await app.inject({
    method: 'POST',
    url: '/api/wallet/gold/buy',
    headers: { ...authHeader(token), 'content-type': 'application/json' },
    payload: JSON.stringify({ grams: 0.000_000_5 }),
  })
  assert.equal(subToman.statusCode, 400)

  const highPrecision = await app.inject({
    method: 'POST',
    url: '/api/wallet/gold/buy',
    headers: { ...authHeader(token), 'content-type': 'application/json' },
    payload: JSON.stringify({ grams: 0.000_001_5 }),
  })
  assert.equal(highPrecision.statusCode, 400)
  assert.equal(parseJson<{ error: string }>(highPrecision.payload).error, 'دقت مقدار طلا بیش از حد مجاز است')

  const userId = await seedWallet(app, token, 500_000, 0)
  const db = app.get(DatabaseService)
  const stateBeforeFail = (
    db.getDb().prepare('SELECT state_json FROM users WHERE id = ?').get(userId) as { state_json: string }
  ).state_json

  const insufficient = await app.inject({
    method: 'POST',
    url: '/api/wallet/gold/buy',
    headers: authHeader(token),
    payload: { grams: 1000 },
  })
  assert.equal(insufficient.statusCode, 400)
  const stateAfterFail = (
    db.getDb().prepare('SELECT state_json FROM users WHERE id = ?').get(userId) as { state_json: string }
  ).state_json
  assert.equal(stateAfterFail, stateBeforeFail)

  const buy = await app.inject({
    method: 'POST',
    url: '/api/wallet/gold/buy',
    headers: { ...authHeader(token), 'content-type': 'application/json' },
    payload: JSON.stringify({ grams: 0.000_001 }),
  })
  assert.equal(buy.statusCode, 200)
  const buyBody = parseJson<{ wallet: { cash: number; goldGrams: number } }>(buy.payload)
  assert.equal(buyBody.wallet.goldGrams, 0.000_001)
  assert.equal(buyBody.wallet.cash, 500_000 - tomansForGoldPurchase(0.000_001))
}

async function runTests() {
  unitTests()
  const app = await createApp()
  try {
    await apiTests(app)
    console.log('gold-precision tests passed')
  } finally {
    await app.close()
    try {
      rmSync(testDir, { recursive: true, force: true })
    } catch {
      // ignore
    }
  }
}

runTests().catch((error) => {
  console.error(error)
  process.exit(1)
})